The string parsing routine may end up writing beyond bounds of tunestr
if the input tunable string is malformed, of the form name=name=val.
This gets processed twice, first as name=name=val and next as name=val,
resulting in tunestr being name=name=val:name=val, thus overflowing
tunestr.
Terminate the parsing loop at the first instance itself so that tunestr
does not overflow.
This also fixes up tst-env-setuid-tunables to actually handle failures
correct and add new tests to validate the fix for this CVE.
Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
(cherry picked from commit 1056e5b4c3)
When parse_tunables tries to erase a tunable marked as SXID_ERASE for
setuid programs, it ends up setting the envvar string iterator
incorrectly, because of which it may parse the next tunable
incorrectly. Given that currently the implementation allows malformed
and unrecognized tunables pass through, it may even allow SXID_ERASE
tunables to go through.
This change revamps the SXID_ERASE implementation so that:
- Only valid tunables are written back to the tunestr string, because
of which children of SXID programs will only inherit a clean list of
identified tunables that are not SXID_ERASE.
- Unrecognized tunables get scrubbed off from the environment and
subsequently from the child environment.
- This has the side-effect that a tunable that is not identified by
the setxid binary, will not be passed on to a non-setxid child even
if the child could have identified that tunable. This may break
applications that expect this behaviour but expecting such tunables
to cross the SXID boundary is wrong.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
The simplification of tunable_set interfaces took care of
signed/unsigned conversions while setting values, but comparison with
bounds ended up being incorrect; comparing TUNABLE_SIZE_T values for
example will fail because SIZE_MAX is seen as -1.
Add comparison helpers that take tunable types into account and use
them to do comparison instead.
The TUNABLE_SET interface took a primitive C type argument, which
resulted in inconsistent type conversions internally due to incorrect
dereferencing of types, especialy on 32-bit architectures. This
change simplifies the TUNABLE setting logic along with the interfaces.
Now all numeric tunable values are stored as signed numbers in
tunable_num_t, which is intmax_t. All calls to set tunables cast the
input value to its primitive type and then to tunable_num_t for
storage. This relies on gcc-specific (although I suspect other
compilers woul also do the same) unsigned to signed integer conversion
semantics, i.e. the bit pattern is conserved. The reverse conversion
is guaranteed by the standard.
Extern symbol access in position independent code usually involves GOT
indirection which needs RELATIVE reloc in a static linked PIE. (On
some targets this is avoided e.g. because the linker can relax a GOT
access to a pc-relative access, but this is not generally true.) Code
that runs before static PIE self relocation must avoid relying on
dynamic relocations which can be ensured by using hidden visibility.
However we cannot just make all symbols hidden:
On i386, all calls to IFUNC functions must go through PLT and calls to
hidden functions CANNOT go through PLT in PIE since EBX used in PIE PLT
may not be set up for local calls to hidden IFUNC functions.
This patch aims to make symbol references hidden in code that is used
before and by _dl_relocate_static_pie when building a static PIE libc.
Note: for an object that is used in the startup code, its references
and definition may not have consistent visibility: it is only forced
hidden in the startup code.
This is needed for fixing bug 27072.
Co-authored-by: H.J. Lu <hjl.tools@gmail.com>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
With static pie linking pointers in the tunables list need
RELATIVE relocs since the absolute address is not known at link
time. We want to avoid relocations so the static pie self
relocation can be done after tunables are initialized.
This is a simple fix that embeds the tunable strings into the
tunable list instead of using pointers. It is possible to have
a more compact representation of tunables with some additional
complexity in the generator and tunable parser logic. Such
optimization will be useful if the list of tunables grows.
There is still an issue that tunables_strdup allocates and the
failure handling code path is sufficiently complex that it can
easily have RELATIVE relocations. It is possible to avoid the
early allocation and only change environment variables in a
setuid exe after relocations are processed. But that is a
bigger change and early failure is fatal anyway so it is not
as critical to fix right away. This is bug 27181.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
I used these shell commands:
../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")
and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 6694 files FOO.
I then removed trailing white space from benchtests/bench-pthread-locks.c
and iconvdata/tst-iconv-big5-hkscs-to-2ucs4.c, to work around this
diagnostic from Savannah:
remote: *** pre-commit check failed ...
remote: *** error: lines with trailing whitespace found
remote: error: hook declined to update refs/heads/master
Some tunable values and their minimum/maximum values must be determinted
at run-time. Add TUNABLE_SET_WITH_BOUNDS and TUNABLE_SET_WITH_BOUNDS_FULL
to update tunable value together with minimum and maximum values.
__tunable_set_val is updated to set tunable value as well as min/max
values.
There are:
#define TUNABLE_SET_VAL_IF_VALID_RANGE(__cur, __val, __type) \
({ \
__type min = (__cur)->type.min; \
__type max = (__cur)->type.max; \
\
if ((__type) (__val) >= min && (__type) (val) <= max) \
^^^ Should be __val
{ \
(__cur)->val.numval = val; \
^^^ Should be __val
(__cur)->initialized = true; \
} \
})
Luckily since all TUNABLE_SET_VAL_IF_VALID_RANGE usages are
TUNABLE_SET_VAL_IF_VALID_RANGE (cur, val, int64_t);
this didn't cause any issues.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
One group of warnings seen with -Wextra is warnings for static or
inline not at the start of a declaration (-Wold-style-declaration).
This patch fixes various such cases for inline, ensuring it comes at
the start of the declaration (after any static). A common case of the
fix is "static inline <type> __always_inline"; the definition of
__always_inline starts with __inline, so the natural change is to
"static __always_inline <type>". Other cases of the warning may be
harder to fix (one pattern is a function definition that gets
rewritten to be static by an including file, "#define funcname static
wrapped_funcname" or similar), but it seems worth fixing these cases
with inline anyway.
Tested for x86_64.
* elf/dl-load.h (_dl_postprocess_loadcmd): Use __always_inline
before return type, without separate inline.
* elf/dl-tunables.c (maybe_enable_malloc_check): Likewise.
* elf/dl-tunables.h (tunable_is_name): Likewise.
* malloc/malloc.c (do_set_trim_threshold): Likewise.
(do_set_top_pad): Likewise.
(do_set_mmap_threshold): Likewise.
(do_set_mmaps_max): Likewise.
(do_set_mallopt_check): Likewise.
(do_set_perturb_byte): Likewise.
(do_set_arena_test): Likewise.
(do_set_arena_max): Likewise.
(do_set_tcache_max): Likewise.
(do_set_tcache_count): Likewise.
(do_set_tcache_unsorted_limit): Likewise.
* nis/nis_subr.c (count_dots): Likewise.
* nptl/allocatestack.c (advise_stack_range): Likewise.
* sysdeps/ieee754/dbl-64/s_sin.c (do_cos): Likewise.
(do_sin): Likewise.
(reduce_sincos): Likewise.
(do_sincos): Likewise.
* sysdeps/unix/sysv/linux/x86/elision-conf.c
(do_set_elision_enable): Likewise.
(TUNABLE_CALLBACK_FNDECL): Likewise.
Current implementation of tunables does not set arena_max and arena_test
values. Any value provided by glibc.malloc.arena_max and
glibc.malloc.arena_test parameters is ignored.
These tunables have minval value set to 1 (see elf/dl-tunables.list file)
and undefined maxval value. In that case default value (which is 0. see
scripts/gen-tunables.awk) is being used to set maxval.
For instance, generated tunable_list[] entry for arena_max is:
(gdb) p *cur
$1 = {name = 0x7ffff7df6217 "glibc.malloc.arena_max",
type = {type_code = TUNABLE_TYPE_SIZE_T, min = 1, max = 0},
val = {numval = 0, strval = 0x0}, initialized = false,
security_level = TUNABLE_SECLEVEL_SXID_IGNORE,
env_alias = 0x7ffff7df622e "MALLOC_ARENA_MAX"}
As a result, any value of glibc.malloc.arena_max is ignored by
TUNABLE_SET_VAL_IF_VALID_RANGE macro
__type min = (__cur)->type.min; <- initialized to 1
__type max = (__cur)->type.max; <- initialized to 0!
if (min == max) <- false
{
min = __default_min;
max = __default_max;
}
if ((__type) (__val) >= min && (__type) (val) <= max) <- false
{
(__cur)->val.numval = val;
(__cur)->initialized = true;
}
Assigning correct min/max values at a build time fixes a problem.
Plus, a bit of optimization: Setting of default min/max values for the
given type at a run time might be eliminated.
* elf/dl-tunables.c (do_tunable_update_val): Range checking fix.
* scripts/gen-tunables.awk: Set unspecified minval and/or maxval
values to correct default value for given type.
On Linux/i386, there are 3 ways to make a system call:
1. call *%gs:SYSINFO_OFFSET. This requires TLS initialization.
2. call *_dl_sysinfo. This requires relocation of _dl_sysinfo.
3. int $0x80. This is slower than #2 and #3, but works everywhere.
When an object file is compiled with PIC, #1 is prefered since it is
faster than #3 and doesn't require relocation of _dl_sysinfo. For
dynamic executables, ld.so initializes TLS. However, for static
executables, before TLS is initialized by __libc_setup_tls, #3 should
be used for system calls.
This patch adds <startup.h> which defines _startup_fatal and defaults
it to __libc_fatal. It replaces __libc_fatal with _startup_fatal in
static executables where it is called before __libc_setup_tls is called.
This header file is included in all files containing functions which are
called before __libc_setup_tls is called. On Linux/i386, when PIE is
enabled by default, _startup_fatal is turned into ABORT_INSTRUCTION and
I386_USE_SYSENTER is defined to 0 so that "int $0x80" is used for system
calls before __libc_setup_tls is called.
Tested on i686 and x86-64. Without this patch, all statically-linked
tests will fail on i686 when the compiler defaults to -fPIE.
[BZ #21913]
* csu/libc-tls.c: Include <startup.h> first.
(__libc_setup_tls): Call _startup_fatal instead of __libc_fatal.
* elf/dl-tunables.c: Include <startup.h> first.
* include/libc-symbols.h (BUILD_PIE_DEFAULT): New.
* sysdeps/generic/startup.h: New file.
* sysdeps/unix/sysv/linux/i386/startup.h: Likewise.
* sysdeps/unix/sysv/linux/i386/brk.c [BUILD_PIE_DEFAULT != 0]
(I386_USE_SYSENTER): New. Defined to 0.
The function maybe_enable_malloc_check, which is called by
__tunables_init, calls __access_noerrno. It isn't problem when
symbol is is in ld.so, which has a special version of __access_noerrno
without stack protector. But when glibc is built with stack protector,
maybe_enable_malloc_check in libc.a can't call the regular version of
__access_noerrno with stack protector.
This patch changes how Linux defines the __access_noerrno to be an
inline call instead and thus preventing defining different build
rules for ld/static and shared.
H.J. Lu <hongjiu.lu@intel.com>
Adhemerval Zanella <adhemerval.zanella@linaro.org>
[BZ #21744]
* elf/dl-tunables.c: Include not-errno.h header.
* include/unistd.h (__access_noerrno): Remove definition.
* sysdeps/unix/sysv/linux/access.c (__access_noerrno): Likewise.
* sysdeps/generic/not-errno.h: New file.
* sysdeps/unix/sysv/linux/not-errno.h: Likewise.
Add a new tunable (glibc.tune.cpu) to override CPU identification on
aarch64. This is useful in two cases: one where it is desirable to
pretend to be another CPU for purposes of testing or because routines
written for that CPU are beneficial for specific workloads and second
where the underlying kernel does not support emulation of MRS to get
the MIDR of the CPU.
* elf/dl-tunables.h (tunable_is_name): Move from...
* elf/dl-tunables.c (is_name): ... here.
(parse_tunables, __tunables_init): Adjust.
* manual/tunables.texi: Document glibc.tune.cpu.
* sysdeps/aarch64/dl-tunables.list: New file.
* sysdeps/unix/sysv/linux/aarch64/cpu-features.c (struct
cpu_list): New type.
(cpu_list): New list of CPU names and their MIDR.
(get_midr_from_mcpu): New function.
(init_cpu_features): Override MIDR if necessary.
There are 2 minimal strtoul implementations in ld.so:
1. __strtoul_internal in elf/dl-minimal.c.
2. tunables_strtoul in elf/dl-tunables.c.
This patch adds _dl_strtoul to replace them. Tested builds with and
without --enable-tunables.
[BZ #21528]
* elf/dl-minimal.c (__strtoul_internal): Removed.
(strtoul): Likewise.
* elf/dl-misc.c (_dl_strtoul): New function.
* elf/dl-tunables.c (tunables_strtoul): Removed.
(tunable_initialize): Replace tunables_strtoul with _dl_strtoul.
* elf/rtld.c (process_envvars): Likewise.
* sysdeps/unix/sysv/linux/dl-librecon.h (_dl_osversion_init):
Likewise.
* sysdeps/generic/ldsodefs.h (_dl_strtoul): New prototype.
The TUNABLE_SET_VALUE and family of macros (and my later attempt to
add a TUNABLE_GET) never quite went together very well because the
overall interface was not clearly defined. This patch is an attempt
to do just that.
This patch consolidates the API to two simple sets of macros,
TUNABLE_GET* and TUNABLE_SET*. If TUNABLE_NAMESPACE is defined,
TUNABLE_GET takes just the tunable name, type and a (optionally NULL)
callback function to get the value of the tunable. The callback
function, if non-NULL, is called if the tunable was externally set
(i.e. via GLIBC_TUNABLES or any future mechanism). For example:
val = TUNABLE_GET (check, int32_t, check_callback)
returns the value of the glibc.malloc.check tunable (assuming
TUNABLE_NAMESPACE is set to malloc) as an int32_t into VAL after
calling check_callback.
Likewise, TUNABLE_SET can be used to set the value of the tunable,
although this is currently possible only in the dynamic linker before
it relocates itself. For example:
TUNABLE_SET (check, int32_t, 2)
will set glibc.malloc.check to 2. Of course, this is not possible
since we set (or read) glibc.malloc.check long after it is relocated.
To access or set a tunable outside of TUNABLE_NAMESPACE, use the
TUNABLE_GET_FULL and TUNABLE_SET_FULL macros, which have the following
prototype:
TUNABLE_GET_FULL (glibc, tune, hwcap_mask, uint64_t, NULL)
TUNABLE_SET_FULL (glibc, tune, hwcap_mask, uint64_t, 0xffff)
In future the tunable list may get split into mutable and immutable
tunables where mutable tunables can be modified by the library and
userspace after relocation as well and TUNABLE_SET will be more useful
than it currently is. However whenever we actually do that split, we
will have to ensure that the mutable tunables are protected with
locks.
* elf/Versions (__tunable_set_val): Rename to __tunable_get_val.
* elf/dl-tunables.c: Likewise.
(do_tunable_update_val): New function.
(__tunable_set_val): New function.
(__tunable_get_val): Call CB only if the tunable was externally
initialized.
(tunables_strtoul): Replace strval with initialized.
* elf/dl-tunables.h (strval): Replace with a bool initialized.
(TUNABLE_ENUM_NAME, TUNABLE_ENUM_NAME1): Adjust names to
prevent collision.
(__tunable_set_val): New function.
(TUNABLE_GET, TUNABLE_GET_FULL): New macros.
(TUNABLE_SET, TUNABLE_SET_FULL): Likewise.
(TUNABLE_SET_VAL): Remove.
(TUNABLE_SET_VAL_WITH_CALLBACK): Likewise.
* README.tunables: Document the new macros.
* malloc/arena.c (ptmalloc_init): Adjust.
Since __tunables_init is internal to ld.so, we should mark it hidden
to avoid PLT. We should also avoid PLT when calling __tunable_set_val
within ld.so.
2017-05-25 Siddhesh Poyarekar <siddhesh@sourceware.org>
H.J. Lu <hongjiu.lu@intel.com>
* elf/dl-tunables.c (__tunable_set_val): Make a hidden alias.
* elf/dl-tunables.h (__tunables_init): Mark it hidden in rtld.
(__tunable_set_val): Likewise.
Recognize the uint64_t type in addition to the current int32_t and
size_t. This allows addition of tunables of uint64_t types. In
addition to adding the uint64_t type, this patch also consolidates
validation and reading of integer types in tunables.
One notable change is that of overflow computation in
tunables_strtoul. The function was lifted from __internal_strtoul,
but it does not need the boundary condition check (i.e. result ==
ULONG_MAX) since it does not need to set errno. As a result the check
can be simplified, which I have now done.
* elf/dl-tunable-types.h (tunable_type_code_t): New type
TUNABLE_TYPE_UINT_64.
* elf/dl-tunables.c (tunables_strtoul): Return uint64_t.
Simplify computation of overflow.
(tunable_set_val_if_valid_range_signed,
tunable_set_val_if_valid_range_unsigned): Remove and replace
with this...
(TUNABLE_SET_VAL_IF_VALID_RANGE): ... New macro.
(tunable_initialize): Adjust. Add uint64_t support.
(__tunable_set_val): Add uint64_t support.
* README.tunables: Document it.
posix/wordexp-test.c used libc-internal.h for PTR_ALIGN_DOWN; similar
to what was done with libc-diag.h, I have split the definitions of
cast_to_integer, ALIGN_UP, ALIGN_DOWN, PTR_ALIGN_UP, and PTR_ALIGN_DOWN
to a new header, libc-pointer-arith.h.
It then occurred to me that the remaining declarations in libc-internal.h
are mostly to do with early initialization, and probably most of the
files including it, even in the core code, don't need it anymore. Indeed,
only 19 files actually need what remains of libc-internal.h. 23 others
need libc-diag.h instead, and 12 need libc-pointer-arith.h instead.
No file needs more than one of them, and 16 don't need any of them!
So, with this patch, libc-internal.h stops including libc-diag.h as
well as losing the pointer arithmetic macros, and all including files
are adjusted.
* include/libc-pointer-arith.h: New file. Define
cast_to_integer, ALIGN_UP, ALIGN_DOWN, PTR_ALIGN_UP, and
PTR_ALIGN_DOWN here.
* include/libc-internal.h: Definitions of above macros
moved from here. Don't include libc-diag.h anymore either.
* posix/wordexp-test.c: Include stdint.h and libc-pointer-arith.h.
Don't include libc-internal.h.
* debug/pcprofile.c, elf/dl-tunables.c, elf/soinit.c, io/openat.c
* io/openat64.c, misc/ptrace.c, nptl/pthread_clock_gettime.c
* nptl/pthread_clock_settime.c, nptl/pthread_cond_common.c
* string/strcoll_l.c, sysdeps/nacl/brk.c
* sysdeps/unix/clock_settime.c
* sysdeps/unix/sysv/linux/i386/get_clockfreq.c
* sysdeps/unix/sysv/linux/ia64/get_clockfreq.c
* sysdeps/unix/sysv/linux/powerpc/get_clockfreq.c
* sysdeps/unix/sysv/linux/sparc/sparc64/get_clockfreq.c:
Don't include libc-internal.h.
* elf/get-dynamic-info.h, iconv/loop.c
* iconvdata/iso-2022-cn-ext.c, locale/weight.h, locale/weightwc.h
* misc/reboot.c, nis/nis_table.c, nptl_db/thread_dbP.h
* nscd/connections.c, resolv/res_send.c, soft-fp/fmadf4.c
* soft-fp/fmasf4.c, soft-fp/fmatf4.c, stdio-common/vfscanf.c
* sysdeps/ieee754/dbl-64/e_lgamma_r.c
* sysdeps/ieee754/dbl-64/k_rem_pio2.c
* sysdeps/ieee754/flt-32/e_lgammaf_r.c
* sysdeps/ieee754/flt-32/k_rem_pio2f.c
* sysdeps/ieee754/ldbl-128/k_tanl.c
* sysdeps/ieee754/ldbl-128ibm/k_tanl.c
* sysdeps/ieee754/ldbl-96/e_lgammal_r.c
* sysdeps/ieee754/ldbl-96/k_tanl.c, sysdeps/nptl/futex-internal.h:
Include libc-diag.h instead of libc-internal.h.
* elf/dl-load.c, elf/dl-reloc.c, locale/programs/locarchive.c
* nptl/nptl-init.c, string/strcspn.c, string/strspn.c
* malloc/malloc.c, sysdeps/i386/nptl/tls.h
* sysdeps/nacl/dl-map-segments.h, sysdeps/x86_64/atomic-machine.h
* sysdeps/unix/sysv/linux/spawni.c
* sysdeps/x86_64/nptl/tls.h:
Include libc-pointer-arith.h instead of libc-internal.h.
* elf/get-dynamic-info.h, sysdeps/nacl/dl-map-segments.h
* sysdeps/x86_64/atomic-machine.h:
Add multiple include guard.
The code to set value passed a tunable_val_t, which when cast to
int32_t on big-endian gives the wrong value. Instead, use
tunable_val_t.numval instead, which can then be safely cast into
int32_t.
Florian Weimer pointed out that we have three different kinds of
environment variables (and hence tunables):
1. Variables that are removed for setxid processes
2. Variables that are ignored in setxid processes but is passed on to
child processes
3. Variables that are passed on to child processes all the time
Tunables currently only does (2) and (3) when it should be doing (1)
for MALLOC_CHECK_. This patch enhances the is_secure flag in tunables
to an enum value that can specify which of the above three categories
the tunable (and its envvar alias) belongs to.
The default is for tunables to be in (1). Hence, all of the malloc
tunables barring MALLOC_CHECK_ are explicitly specified to belong to
category (2). There were discussions around abolishing category (2)
completely but we can do that as a separate exercise in 2.26.
Tested on x86_64 to verify that there are no regressions.
[BZ #21073]
* elf/dl-tunable-types.h (tunable_seclevel_t): New enum.
* elf/dl-tunables.c (tunables_strdup): Remove.
(get_next_env): Also return the previous envp.
(parse_tunables): Erase tunables of category
TUNABLES_SECLEVEL_SXID_ERASE.
(maybe_enable_malloc_check): Make MALLOC_CHECK_
TUNABLE_SECLEVEL_NONE if /etc/setuid-debug is accessible.
(__tunables_init)[TUNABLES_FRONTEND ==
TUNABLES_FRONTEND_valstring]: Update GLIBC_TUNABLES envvar
after parsing.
[TUNABLES_FRONTEND != TUNABLES_FRONTEND_valstring]: Erase
tunable envvars of category TUNABLES_SECLEVEL_SXID_ERASE.
* elf/dl-tunables.h (struct _tunable): Change member is_secure
to security_level.
* elf/dl-tunables.list: Add security_level annotations for all
tunables.
* scripts/gen-tunables.awk: Recognize and generate enum values
for security_level.
* elf/tst-env-setuid.c: New test case.
* elf/tst-env-setuid-tunables: new test case.
* elf/Makefile (tests-static): Add them.
(tunable_set_val_if_valid_range_signed) ... this, and ...
(tunable_set_val_if_valid_range_unsigned) ... this.
(tunable_initialize): Call the correct one of the above based on type.
The condition when the value of an envvar is empty (not just '\0'),
the loop in tunables_init gets stuck infinitely because envp is not
incremented. Fix that by always incrementing envp in the loop.
Added test case (tst-empty-env.c) verifies the fix when the source is
configured with --enable-hardcoded-path-in-tests, thanks Josh Stone for
providing the test case. Verified on x86_64.
* elf/dl-tunables (get_next_env): Always advance envp.
* stdlib/tst-empty-env.c: New test case.
* stdlib/Makefile (tests): Use it.
Builds with --enable-tunables failed on i686 because a call to getenv
got snuck into tunables, which pulled in strncmp. This patch fixes
this build failure by making the glibc.malloc.check check even
simpler. The previous approach was convoluted where the tunable was
disabled using an unsetenv and overwriting the tunable value with
colons. The easier way is to simply mark the tunable as insecure by
default (i.e. won't be read for AT_SECURE programs) and then enabled
only when the /etc/suid-debug file is found.
This also ends up removing a bunch of functions that were specially
reimplemented (strlen, unsetenv) to avoid calling into string
routines.
Tested on x86_64 and i686.
* elf/dl-tunables.c (tunables_unsetenv): Remove function.
(min_strlen): Likewise.
(disable_tunable): Likewise.
(maybe_disable_malloc_check): Rename to
maybe_enable_malloc_check.
(maybe_enable_malloc_check): Enable glibc.malloc.check tunable
if /etc/suid-debug file exists.
(__tunables_init): Update caller.
* elf/dl-tunables.list (glibc.malloc.check): Don't mark as
secure.
At the GNU Tools Cauldron 2016, the state of the current tunables
patchset was considered OK with the addition of a way to select the
frontend to be used for the tunables. That is, to avoid being locked
in to one type of frontend initially, it should be possible to build
tunables with a different frontend with something as simple as a
configure switch.
To that effect, this patch enhances the --enable-tunables option to
accept more values than just 'yes' or 'no'. The current frontend (and
default when enable-tunables is 'yes') is called 'valstring', to
select the frontend where a single environment variable is set to a
colon-separated value string. More such frontends can be added in
future.
* Makeconfig (have-tunables): Check for non-negative instead
of positive.
* configure.ac: Add 'valstring' as a valid value for
--enable-tunables.
* configure: Regenerate.
* elf/Makefile (have-tunables): Check for non-negative instead
of positive.
(CPPFLAGS-dl-tunables.c): Define TUNABLES_FRONTEND for
dl-tunables.c.
* elf/dl-tunables.c (GLIBC_TUNABLES): Define only when
TUNABLES_FRONTEND == TUNABLES_FRONTEND_valstring.
(tunables_strdup): Likewise.
(disable_tunables): Likewise.
(parse_tunables): Likewise.
(__tunables_init): Process GLIBC_TUNABLES envvar only when.
TUNABLES_FRONTEND == TUNABLES_FRONTEND_valstring.
* elf/dl-tunables.h (TUNABLES_FRONTEND_valstring): New macro.
(TUNABLES_FRONTEND_yes): New macro, define as
TUNABLES_FRONTEND_valstring by default.
* manual/install.texi: Document new acceptable values for
--enable-tunables.
* INSTALL: Regenerate.
Read tunables values from the users using the GLIBC_TUNABLES
environment variable. The value of this variable is a colon-separated
list of name=value pairs. So a typical string would look like this:
GLIBC_TUNABLES=glibc.malloc.mmap_threshold=2048:glibc.malloc.trim_threshold=1024
* config.make.in (have-loop-to-function): Define.
* elf/Makefile (CFLAGS-dl-tunables.c): Add
-fno-tree-loop-distribute-patterns.
* elf/dl-tunables.c: Include libc-internals.h.
(GLIBC_TUNABLES): New macro.
(tunables_strdup): New function.
(parse_tunables): New function.
(min_strlen): New function.
(__tunables_init): Use the new functions and macro.
(disable_tunable): Disable tunable from GLIBC_TUNABLES.
* malloc/tst-malloc-usable-tunables.c: New test case.
* malloc/tst-malloc-usable-static-tunables.c: New test case.
* malloc/Makefile (tests, tests-static): Add tests.
The tunables framework allows us to uniformly manage and expose global
variables inside glibc as switches to users. tunables/README has
instructions for glibc developers to add new tunables.
Tunables support can be enabled by passing the --enable-tunables
configure flag to the configure script. This patch only adds a
framework and does not pose any limitations on how tunable values are
read from the user. It also adds environment variables used in malloc
behaviour tweaking to the tunables framework as a PoC of the
compatibility interface.
* manual/install.texi: Add --enable-tunables option.
* INSTALL: Regenerate.
* README.tunables: New file.
* Makeconfig (CPPFLAGS): Define TOP_NAMESPACE.
(before-compile): Generate dl-tunable-list.h early.
* config.h.in: Add HAVE_TUNABLES.
* config.make.in: Add have-tunables.
* configure.ac: Add --enable-tunables option.
* configure: Regenerate.
* csu/init-first.c (__libc_init_first): Move
__libc_init_secure earlier...
* csu/init-first.c (LIBC_START_MAIN):... to here.
Include dl-tunables.h, libc-internal.h.
(LIBC_START_MAIN) [!SHARED]: Initialize tunables for static
binaries.
* elf/Makefile (dl-routines): Add dl-tunables.
* elf/Versions (ld): Add __tunable_set_val to GLIBC_PRIVATE
namespace.
* elf/dl-support (_dl_nondynamic_init): Unset MALLOC_CHECK_
only when !HAVE_TUNABLES.
* elf/rtld.c (process_envvars): Likewise.
* elf/dl-sysdep.c [HAVE_TUNABLES]: Include dl-tunables.h
(_dl_sysdep_start): Call __tunables_init.
* elf/dl-tunable-types.h: New file.
* elf/dl-tunables.c: New file.
* elf/dl-tunables.h: New file.
* elf/dl-tunables.list: New file.
* malloc/tst-malloc-usable-static.c: New test case.
* malloc/Makefile (tests-static): Add it.
* malloc/arena.c [HAVE_TUNABLES]: Include dl-tunables.h.
Define TUNABLE_NAMESPACE.
(DL_TUNABLE_CALLBACK (set_mallopt_check)): New function.
(DL_TUNABLE_CALLBACK_FNDECL): New macro. Use it to define
callback functions.
(ptmalloc_init): Set tunable values.
* scripts/gen-tunables.awk: New file.
* sysdeps/mach/hurd/dl-sysdep.c: Include dl-tunables.h.
(_dl_sysdep_start): Call __tunables_init.
